Process for the preparation of N-alkenylphenylmaleimides and N,N&#39;-[alkenylenephenylene]bismalemides

ABSTRACT

Disclosed are novel alkenylphenylmaleimide derivatives having the general formula ##STR1## where R is an alkenyl radical of from 3 to 12 carbon atoms, R&#39; is a hydrogen atom, a halogen atom, or a straight-chain or branched alkyl radical of from 1 to 4 carbon atoms, and n is a whole number of from 1 to 4, and linear dimers thereof as well as a process for the preparation of such maleimide compounds.

This is a division of application Ser. No. 131,804, filed Mar. 19, 1980now U.S. Pat. No. 4,376,206 issued Mar. 8, 1983.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

This invention relates to novel alkenylphenylmaleimide derivatives andlinear dimers thereof which have high thermal decompositiontemperatures, exhibit rapid curability, and are easily soluble in commonorganic solvents. In another aspect, it relates to a process for thepreparation of such maleimide compounds.

(2) Description of the Prior Art

A variety of heat resistant resins have been developed as insulatingmaterials meeting the constant demands for greater capacity,miniaturization and weight-saving, improved reliability and thermalstability, longer lifetime, maintenance-free properties, etc. ofelectronic devices and apparatus. Generally, bismaleimides (includingN,N'-(methylenedi-p-phenylene)bismaleimide as a typical example)obtained by reacting a primary amine with maleic anhydride providethermosetting resins having excellent heat resistance and a densestructure. However, these maleimides are high in melting point andsparingly soluble in common organic solvents. Accordingly, if it isdesired to use them in the form of a solution, they must be dissolved inhigh-boiling polar organic solvents, such as dimethylformamide,dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, etc., thatare undesirable for reasons of safety and health. Moreover, when animpregnating varnish prepared by reacting such a bismaleimide with adiamine and dissolving the resulting prepolymer in dimethylformamide orN-methylpyrrolidone is used in the fabrication of copper-clad laminates,removal of the solvent is so difficult that gas bubbles, blisters of thecopper foil, and other defects may develop. Because of this greattechnical disadvantage, the needs of the times have recently changedfrom impregnating varnishes of the solution type to ones of thesolventless type. In order to solve the above-described problems, therehave been proposed, for example, a method of modifyingpoly(phenylmethylene)polymaleimide by incorporating an poxy resinthereinto (Japanese Patent Laid-open No. 21098/'75) and a method ofmodifying a prepolymer of a bismaleimide and a polyamine byincorporating an epoxy resin thereinto (Japanese Patent Publication No.27519/'75). In these modified maleimide compositions, however, themaleimide tends to precipitate at temperatures in the vicinity of roomtemperature and the limitation placed on the maleimide content preventsthe achievement of satisfactory heat resistance and adhesion properties.Thus, they are not suitable for practical use as industrial materialsrequired to have high performance.

In the prior art, processes for preparing maleimides, bismaleimides, andpolymaleimides are well known and one example thereof is disclosed inU.S. Pat. No. 4,130,564. However, the maleimide compounds of the presentinvention cannot satisfactorily be prepared according to this process.Specifically, since the maleimide compounds of the present inventionhave high solubility in organic solvents and great affinity for organicsolvents, they cannot sufficiently be crystallized by cooling thereaction mixture after completion of the maleimide-forming reaction.Moreover, if a bad solvent such as water or the like is used toprecipitate the formed maleimide compound (alkenylphenylmaleimidederivative or linear dimer thereof) from the reaction mixture, themaleimide compound undergoes a marked degree of agglomeration and failsto remain in the form of particles of proper size. Furthermore, themaleimide compound precipitated by a large amount of bad solvent is avery impure product containing various byproducts and must therefore bepurified by recrystallization from a special organic solvent such asacetonitrile or the like. Thus, the prior art fails to provide atechnologically simple and industrially advantageous process forpreparing the maleimide compounds of the present invention.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide novelalkenylphenylmaleimide derivatives and linear dimers thereof.

It is another object of the present invention to provide novelalkenylphenylmaleimide derivatives and linear dimers thereof which areeasily soluble in common organic solvents, have high thermaldecomposition temperatures, and exhibit such properties as rapidcurability, homopolymerizability, and the like.

It is a further object of the present invention to provide novelalkenylphenylmaleimide derivatives and linear dimers thereof which cangive thermosetting resins having excellent electrical properties,mechanical properties, and thermal stability and which are useful invarious other applications.

It is a still further object of the present invention to provide aprocess for the preparation of such novel alkenylphenylmaleimidederivatives and linear dimers thereof.

DETAILED DESCRIPTION OF THE INVENTION

According to the present invention, there are providedalkenylphenylmaleimide derivatives having the general formula ##STR2##where R is an alkenyl radical of from 3 to 12 carbon atoms, R' is ahydrogen atom, a halogen atom, or a straight-chain or branched alkylradical of from 1 to 4 carbon atoms, and n is a whole number of from 1to 4, and linear dimers of like or different alkenylphenylmaleimidederivatives having the general formula ##STR3## where R' and R" arehydrogen atoms, halogen atoms, or alkyl radicals of from 1 to 4 carbonatoms, n and m are whole numbers of from 1 to 4, and D is a divalentorganic radical of from 6 to 24 carbon atoms containing acarbon-to-carbon double bond.

The maleimide compounds of the present invention, which have lowermelting points than prior art maleimides, are useful as impregnatingvarnishes of the solventless type. In addition, the maleimide compoundsof the present invention have such rapid curability that the energyrequired for the production of various materials can be saved greatly.Moreover, owing to the reactive double bonds present in the molecule,the maleimide compounds of the present invention cannot onlyhomopolymerize but can also react readily with other compounds to form avariety of curable resins. Furthermore, their high thermal decompositiontemperature permit the formation of resins having excellent thermalstability and their high solubilities in common organic solvents bringabout an enhancement in operating efficiency.

By way of example, the melting points and thermal decompositiontemperatures of two typical maleimide compounds of the present inventionare shown in Table 1, and the solubilities of one typical maleimidecompound of the present invention in several organic solvents are shownin Table 2. The thermal decomposition temperatures were measured in astream of nitrogen gas by means of a thermobalance heated at a rate of10° C. per minutes.

                                      TABLE 1                                     __________________________________________________________________________    Melting Points and Thermal Decomposition Temperatures                         of Maleimide Compounds                                                                                        Melting                                                                            Thermal Decompo-                                                         Point                                                                              sition Temperature*                      Maleimide Compound              (°C.)                                                                       (°C.)                             __________________________________________________________________________    Np-isopropenylphenylmaleimide   109-117                                                                            445                                       ##STR4##                                                                       N,N'(1-methyl-3,3-dimethyl-1-  99-110                                                                            443                                      propenylenedi-p-phenylene)-                                                   bismaleimide                                                                   ##STR5##                                                                     __________________________________________________________________________     *The temperature at which a 5% loss in weight is caused.                 

                  TABLE 2                                                         ______________________________________                                        Solubilities of N--p-isopropenylphenylmaleimide                               Organic Solvent                                                                              Solubility (at room temperature)                               ______________________________________                                        Dimethylformamide                                                                            46.5 wt. % or higher                                           Dioxane        41.5 wt. %                                                     Tetrahydrofuran                                                                              41.0 wt. %                                                     Chloroform     30.0 wt. %                                                     Acetone        23.3 wt. %                                                     Methyl ethyl ketone                                                                          21.7 wt. %                                                     ______________________________________                                    

Typical examples of the novel maleimide compounds represented by thegeneral formulas (I) and (II) include

N-(o-isopropenylphenyl)maleimide,

N-(m-isopropenylphenyl)maleimide,

N-(p-isopropenylphenyl)maleimide,

N-(3-methyl-4-isopropenylphenyl)maleimide,

N-(3-chloro-4-isopropenylphenyl)maleimide,

N-[p-(1-ethylethenyl)phenyl]maleimide,

N-[p-(1-methyl-1-propenyl)phenyl]maleimide,

N-[2-methyl-4-(1'-methyl-1'-propenyl)phenyl]maleimide,

N-[p-(1-propylethenyl)phenyl]maleimide,

N-[p-(1-methyl-1-butenyl)phenyl]maleimide,

N-[3-chloro-4-(1'-methyl-1'-propenyl)phenyl]maleimide,

N,N'-(1-methylene-3,3-dimethyltrimethylenedi-p-phenylene)bismaleimide,

N,N'-(1-methyl-3,3-dimethyl-1-propenylenedi-p-phenylene)bismaleimide,

N,N'-[1-methylene-3,3-dimethyltrimethylenebis(3'-methyl-1',4'-phenylene)]bismaleimide,

N,N'-[1-methyl-3,3-dimethyl-1-propenylenebis(3'-methyl-1',4'-phenylene)]bismaleimide,

N,N'-(1-methylene-3,3-diethyltrimethylenedi-p-phenylene)bismaleimide,

N,N'-[1-methylene-3,3-diethyltrimethylenebis(3'-chloro-1',4'-phenylene)bismaleimide,

N,N'-(1-methyl-3,3-dipropyl-1-propenylenedi-p-phenylene)bismaleimide,

and the like.

The above-described maleimide compounds of the present invention can beprepared by effecting reaction of an alkenylphenylmaleamic acidderivative having the general formula ##STR6## where R is an alkenylradical of from 3 to 12 carbon atoms, R' is a hydrogen atom, a halogenatom, or a straight-chain or branched alkyl radical of from 1 to 4carbon atoms, and n is a whole number of from 1 to 4, or a linear dimerof like or different alkenylphenylmaleamic acid derivatives having thegeneral formula ##STR7## where R' and R" are hydrogen atoms, halogenatoms, or straight-chain or branched alkyl radicals of from 1 to 4carbon atoms, n and m are whole numbers of from 1 to 4, and D is adivalent organic radical of from 6 to 24 carbon atoms containing acarbon-to-carbon double bond, with a dehydrating agent in the presenceof an organic solvent, a catalyst, and a tertiary amine; and then addingan alcohol to the reaction mixture.

Typical examples of the alkenylphenylmaleamic acid derivativerepresented by the general formula (III) include

N-(o-isopropenylphenyl)maleamic acid,

N-(m-isopropenylphenyl)maleamic acid,

N-(p-isopropenylphenyl)maleamic acid,

N-(2-methyl-4-isopropenylphenyl)maleamic acid,

N-(3-methyl-4-isopropenylphenyl)maleamic acid,

N-(2-chloro-4-isopropenylphenyl)maleamic acid,

N-(2-bromo-4-isopropenylphenyl)maleamic acid,

N-(3-chloro-4-isopropenylphenyl)maleamic acid,

N-(3-bromo-4-isopropenylphenyl)maleamic acid,

N-[o-(1-ethylethenyl)phenyl]maleamic acid,

N-[p-(1-ethylethenyl)phenyl]maleamic acid,

N-[o-(1-methyl-1-propenyl)phenyl]maleamic acid,

N-[p-(1-methyl-1-propenyl)phenyl]maleamic acid,

N-[2-methyl-4-(1'-methyl-1'-propenyl)phenyl]maleamic acid,

N-[2-chloro-4-(1'-methyl-1'-propenyl)phenyl]maleamic acid,

N-[2-bromo-4-(1'-methyl-1'-propenyl)phenyl]maleamic acid, and the like.The linear dimer of like or different alkenylphenylmaleamic acidderivatives represented by the general formula (IV) is a bismaleamicacid consisting of a dimerization product of like or different monomersas described above, and typical examples thereof includeN,N'-(1-methylene-3,3-dimethyl-trimethylenedi-p-phenylene)bismaleamicacid,

N,N'-(1-methyl-3,3-dimethyl-1-propenylenedi-p-phenylene)bismaleamicacid,

N,N'-[1-methylene-3,3-dimethyltrimethylenebis(3'-methyl-1',4'-phenylene)]bismaleamicacid,

N,N'-[1-methyl-3,3-dimethyl-1-propenylenebis(3'-methyl-1',4'-phenylene)]bismaleamicacid,

N,N'-[1-methylene-3,3-dimethyltrimethylenebis(3'-chloro-1',4'-phenylene)]bismaleamicacid,

N,N'-(1-methylene-3,3-diethyltrimethylenedi-p-phenylene)-bismaleamicacid,

N,N'-[1-methylene-3,3-diethyltrimethylenebis(3'-chloro-1',4'-phenylene)]bismaleamicacid,

and the like.

The compounds of formulas (III) and (IV) can be prepared by effectingreaction of an alkenylaniline derivative having the general formula##STR8## where R is an alkenyl radical of from 3 to 12 carbon atoms, R'is a hydrogen atom, a halogen atom, or a straight-chain or branchedalkyl radical of from 1 to 4 carbon atoms, and n is a whole number offrom 1 to 4, or a linear dimer thereof with maleic anhydride at atemperature of from 10° to 40° C. in an organic solvent such as acetoneor the like. In order to carry out the process of the present inventionto advantage, the resulting organic solvent solution of thealkenylphenylmaleamic acid derivative or linear dimer thereof may bedirectly used for the cyclodehydration reaction of the present inventionwithout being subjected to any separation step.

The organic solvent which is used in the process of the presentinvention is selected from the group consisting of halogenatedhydrocarbons such as chloroform, methylene chloride, carbontetrachloride, trichloroethylene, etc.; ketones such as acetone, methylethyl ketone, cyclohexanone, etc.; organic carboxylic acids and estersthereof such as formic acid, acetic acid, butyric acid, methyl acetate,ethyl acetate, etc.; alcohols and ethers such as methyl alcohol, ethylalcohol, propyl alcohol, ether, dioxane, tetrahydrofuran, cellosolve,methyl cellosolve, etc.; alicyclic and aromatic hydrocarbons such ascyclohexane, benzene, toluene, xylene (o-, m-, and p-isomers),mesitylene, etc.; aromatic compounds such as chlorobenzene, cresol (o-,m-, and p-isomers), dichlorobenzene (o-, m-, and p-isomers), etc.;nitrogen-containing and sulfur-containing compounds such asacetonitrile, pyridine, N,N-dimethylacetamide, N,N-dimethylformamide,hexamethylphosphoramide, N-methyl-2-pyrrolidone, N-methylcaprolactam,dimethyl sulfoxide, etc.; and the like. Among them, acetone, methylethyl ketone, acetonitrile, tetrahydrofuran, and N,N-dimethylformamideare particularly preferred. These organic solvents may be used alone orin combination. The amount of organic solvent used is preferably from1.1 to 80 times the weight of the alkenylaniline derivative, or lineardimers thereof used as the starting material.

The catalyst which is used for the cyclodehydration reaction in theprocess of the present invention is selected from the group consistingof hydrated or unhydrated inorganic acid salts, organic acid salts, andhalides of sodium, potassium, lithium, iron, nickel, cobalt, copper, andmanganese as well as acetylacetone complexes of the foregoing metals.Typical examples of the catalyst include the hydrated or unhydratedhydrogen carbonate, carbonate, sulfate, nitrate, phosphate,pyrophosphate, acetate, and butyrate of sodium; the hydrated orunhydrated hydrogen carbonate, carbonate, sulfate, nitrate, phosphate,pyrophosphate, acetate, and butyrate of potassium; the hydrated orunhydrated hydrogen carbonate, carbonate, sulfate, nitrate, phosphate,pyrophosphate, chloride, bromide, iodide, acetate, and butyrate oflithium; the hydrated or unhydrated carbonate, sulfate, phosphate,chloride, bromide, iodide, formate, acetate, butyrate, stearte, andnaphthenate of iron (II or III); the hydrated or unhydrated carbonate,sulfate, phosphate, chloride, bromide, iodide, formate, acetate,butyrate, stearate, and naphthenate of nickel (II); the hydrated orunhydrated carbonate, sulfate, phosphate, chloride, bromide, iodide,formate, acetate, butyrate, stearate, and naphthenate of cobalt (II or(III); the hydrate or unhydrated carbonate, sulfate, phosphate,chloride, bromide, iodide, formate, acetate, butyrate, stearate, andnaphthenate of copper (I or II); the hydrated or unhydrated carbonate,sulfate, phosphate, chloride, bromide, iodide, formate, acetate,butyrate, stearate, and naphthenate of manganese (II or III); theacetylacetone complexes of copper (I or II), nickel (II), cobalt (II orIII), and manganese (II or III); and the like. In order to achieve asatisfactory effect, these catalysts may be used alone or incombination. Among them, hydrated or unhydrated sodium acetate, nickel(II) acetate, and cobalt(II) acetate are particularly preferred. Theamount of catalyst used is in this range of from 0.001 to 1.2 moles andpreferably from 0.002 to 0.5 mole per mole of the alkenylphenylmaleamicacid derivative or linear dimer thereof. If the amount of catalyst usedis less than 0.001 mole, the reaction rate is so low that thecyclodehydration reaction requires an unduly long time, while if it isgreater than 1.2 moles, undesirable side reactions take place andthereby reduces the yield of the desired alkenylphenylmaleimidederivative or linear dimer thereof.

The tertiary amine which is used in the process of the present inventionis selected from the group consisting of trialkylamines having alkylradicals of from 3 to 20 carbon atoms (for example, trimethylamine,triethylamine, tributylamine, etc.), N,N-diethylcyclohexylamine,N,N-dimethylbenzylamine, N-methylpiperidine,1,4-diazabicyclo[2.2.2]octane, 1,8-diazabicyclo[5.4.0]7-undecene,N-methylmorpholine, and the like. These tertiary amines may be usedalone or in combination. Among them, triethylamine is particularlypreferred. The amount of tertiary amine used is in the range of from0.01 to 1.1 moles and preferably from 0.05 to 0.6 mole per mole of thealkenylphenylmaleamic acid derivative or linear dimer thereof.

The dehydrating agent which is used in the process of the presentinvention can be any compound that acts on the maleamic acid group ofthe alkenylphenylmaleamic acid derivative or linear dimer thereof toconvert it to the maleimido group and, per se, undergoes hydration orhydrolysis or any compound that has very strong dehydrating power.Typical inorganic dehydrating agents include phosphorus pentoxide,orthophosphoric acid, pyrophosphoric acid, condensed phosphoric acid,sulfuric anhydride, sulfuric acid, sodium sulfate, calcium oxide, bariumoxide, and the like, and typical organic dehydrating agents includecarboxylic acid anhydrides such as acetic anhydride, propionicanhydride, butyric anhydride, valeric anhydride, succinic anhydride,glutaric anhydride, benzoic anhydride, phthalic anhydride, and the like.These dehydrating agents may be used alone or in combination. Amongthem, acetic anhydride is particularly preferred because it is easy tohandle and permits simple after-treatment following the cyclodehydrationreaction. The amount of dehydrating agent used is in the range of from0.2 to 3 moles and preferably from 0.3 to 2 moles per equivalent of themaleamic acid group of the alkenylphenylmaleamic acid derivative orlinear dimer thereof.

In carrying out the process of the present invention, the catalyst, thetertiary amine, and the dehydrating agent may be added in any desiredorder. However, it is preferable to add the catalyst, the tertiaryamine, and the dehydrating agent in that order. If an inorganic compoundsuch as phosphorus pentoxide, orthophosphoric acid, pyrophosphoric acid,condensed phosphoric acid, sulfuric anhydride, sulfuric acid, calciumoxide, barium oxide, or the like is used as the dehydrating agent, thecyclodehydration reaction proceeds without using any particular catalystor tertiary amine. Moreover, dehydrating agents such as condensedphosphoric acid, sulfuric acid, acetic anhydride, and the like can alsoserve as solvents, though it is preferable to carry out thecyclodehydration reaction in the presence of an organic solvent.

The reaction temperature at which the alkenylphenylmaleamic acidderivative or linear dimer thereof undergoes cyclodehydration to formthe corresponding maleimide is in the range of from 0° to 120° C. andpreferable from 30° to 80° C. The reaction time depends on theconcentrations of catalyst and tertiary amine used, the reactiontemperature, and the like, but is in the range of from 0.5 to 9 hoursand preferably from 2 to 5 hours. The cyclodehydration reaction of thepresent invention can proceed under any pressure that maintains thereaction system in the liquid state.

After the cyclodehydration reaction is completed under theabove-described reaction conditions, the reaction mixture is cooled. Asa result, it is obtained in the form of a homogeneous solution or aslurry (when the organic solvent is used in small amounts). Then, thedesired alkenylphenylmaleimide derivative or linear dimer thereof(hereinafter referred to as the maleimide compound) is precipitatedeither by adding a precipitant (for example, water) slowly to thereaction mixture or by adding the reaction mixture dropwise to aprecipitant.

However, the maleimide compound thus obtained is tarry because of itsgreat affinity for the organic solvent. Accordingly, when water is usedas the precipitant, an alcohol is added to the homogeneous reactionmixture after completion of the maleimide-forming reaction in order thatthe maleimide compound may be uniformly dispersed in water and theprecipitate may be obtained in the form of particles of proper size.Typical examples of the alcohol used for this purpose include methylalcohol, ethyl alcohol, 1-propyl alcohol, 2-propyl alcohol, 1-butylalcohol, 2-butyl alcohol, tert-butyl alcohol, and the like. The amountof alcohol used is in the range of from 0.05 to 200 g and preferablyfrom 1.0 to 50 g per 100 g of the reaction mixture. If the amount ofalcohol used is less than 0.05 g, the maleimide compound becomes tarry,while if it is greater than 250 g, the maleimide compound form colloidalparticles which can hardly be separated by filtration. No speciallimitation is placed on the temperature at which the addition of analcohol is carried out, though the preferred temperature range is from5° to 40° C. The reaction mixture having an alcohol added thereto givesa sufficiently pure maleimide compound in the form of particles ofproper size either by adding a precipitant thereto or by adding it to aprecipitant. The precipitant used for this purpose can be any compoundthat dissolves the maleimide compound only to a light degree and hasmiscibility with the solvent of the reaction mixture, and typicalexamples thereof include water, methyl alcohol, ethyl alcohol, 1-propylalcohol, 2-propyl alcohol, 1-butyl alcohol, 2-butyl alcohol, tert-butylalcohol, benzene, toluene, xylene, ethyl isobutyl ether, ethyl isopropylether, chloroform, chlorobenzene, and the like. Among them, water andmethyl alcohol are preferred because they are easy to handle,inexpensive, and harmless to environmental health. The amount ofprecipitant used may be from 0.3 to 50 times the volume of the reactionmixture.

In order to further improve its purity, the maleimide compound thusobtained is usually subjected to an additional purification procedure.Specifically, the precipitate formed in the above-described manner isseparated from the mother liquor. The resulting cake is dispersed againin water to form a slurry. This slurry is neutralized with a basiccompound such as sodium carbonate, sodium hydrogen carbonate, or thelike until its pH reaches a value of from 8.0 to 9.0. Thereafter, theprecipitate is separated, washed several times with water and thoroughlywith methyl alcohol, and then dried to obtain the desired maleimidecompound. In this procedure, the neutralization of a slurry of theprecipitate with a basic compound such as sodium carbonate, sodiumhydrogen carbonate, or the like is not essential to the process of thepresent invention. In fact, a sufficient degree of purification can beachieved simply by washing the precipitate several times with water andthen with an alcohol. However, if a slurry of the precipitate isneutralized with a basic compound, the desired maleimide compound isfurther purified as a result of synergistic effects. Specific examplesof the alcohol used for washing purposes in the process of the presentinvention include methyl alcohol, ethyl alcohol, 1-propyl alcohol,2-propyl alcohol, 1-butyl alcohol, 2-butyl alcohol, and the like. Theamount of alcohol used may be from 1.1 to 30 times the weight of theprecipitate. This washing with an alcohol also has the advantage thatthe time required for drying the maleimide compound thus obtained can bereduced.

The novel maleimide compounds (i.e. alkenylphenylmaleimide derivativesand linear dimers thereof) of the present invention are relativelylow-molecular-weight compounds containing two or more double bonds inthe molecule. They may be used alone or in combination with othersuitable monomers or polymers to form a variety of thermosetting resinswhich can be converted to cured products having the so-calledthree-dimensional network. Such thermosetting resins comprising themaleimide compounds of the present invention are characterized byexcellent heat resistance, good dimensional stability, and easymoldability, and can therefore be widely used in electrical andmechanical applications including impregnating varnishes, laminates,molding materials, coating materials, adhesives, and the like. Inaddition, the maleimide compounds of the present invention also havegreat utility and wide applications in those industrial fields (forexample, agricultural chemicals and rubber chemicals) which requirespecial functions. Moreover, owing to their characteristic propertiessuch as high solubility in organic solvents, low melting point, and thelike, the maleimide compounds of the present invention permitsimplification of operating procedures and offer much saving in energy.

The present invention is further illustrated by the following examples.These examples are illustrative only and are not intended for purposesof limitation.

EXAMPLE 1

Maleic anhydride (43.2 g) was dissolved in 400 ml of acetone. While thissolution was being kept at 20° C., 53.3 g of p-isopropenylaniline wasslowly added thereto with stirring. The resulting reaction mixture wasstirred at 20° C. for 12/3 hours, so that it became a yellow slurry.Then, 0.8 g of cobalt acetate tetrahydrate, 14 g of triethylamine, and50 g of acetic anhydride were added, with stirring, to the above slurry.After completion of the addition, the slurry was heated to 60° C. andstirred at that temperature for 2 hours, so that it became a clear brownsolution. After this solution was cooled to room temperature, 40 ml ofmethyl alcohol was added thereto. The, the solution was slowly pouredinto 4,000 ml of vigorously stirred water. The precipitate so formed wasseparated by filtration and then washed with water, with an aqueoussodium carbonate solution, and thoroughly with water. Thereafter, theprecipitate was dried at 60° C. under reduced pressure to obtain 81 g ofproduct melting at 109°-117° C. Its yield was 95% based on the amount ofp-isopropenylaniline used as the starting material. It was confined byinfrared absorption spectroscopy, nuclear magnetic resonancespectroscopy, and elemental analysis that the product wasN-p-isopropenylphenylmaleimide having the formula ##STR9##

The analytical data were as follows.

    ______________________________________                                        Infrared absorption spectrum:                                                 Group           Absorption Band                                               ______________________________________                                         ##STR10##      1710 cm.sup.-1                                                 ##STR11##      1765 cm.sup.-1                                                ______________________________________                                        N.M.R. spectrum (in DMSO-D.sub.6):                                            Group           δ Value                                                 ______________________________________                                        CH.sub.3        2.12                                                          CH.sub.2        5.11, 5.45                                                     ##STR12##      7.12                                                           ##STR13##      7.28, 7.58                                                    ______________________________________                                        Chemical composition:                                                                        C           H      N                                           ______________________________________                                        Calculated Value (%)                                                                         73.25       5.20   6.57                                        Found Value (%)                                                                              73.12       5.24   6.49                                        ______________________________________                                    

EXAMPLE 2

N,N'-(1-methylene-3,3-dimethyltrimethylenedi-p-phenylene)-bismaleamicacid (46 g) having the formula ##STR14## was dispersed in 300 ml ofacetone to form a slurry. To this slurry were added, with stirring, 0.8g of cobalt acetate tetrahydride and 14 g of triethylamine, and then 26g of acetic anhydride. The resulting reaction mixture was heated to 60°C., kept at that temperature for 21/2 hours, and then cooled to roomtemperature. To this reaction mixture were added 20 ml of methyl alcoholand then 1,500 ml of water. The precipitate so formed was separated byfiltration and dispersed again in water, when was then adjusted to pH9.0 by the addition of sodium carbonate. Thereafter, the precipitate waswashed thoroughly with water. Finally, the precipitate was washed with40 g of methyl alcohol and then dried at 50° C. under reduced pressureto obtain 33 g of product melting at 148°-151° C. Its yield was 77%based on the amount of bismaleamic acid used as the starting material.It was confirmed by infrared absorption spectroscopy, nuclear magneticresonance spectroscopy, and elemental analysis that the product wasN,N'-(1-methylene-3,3-dimethyltrimethylenedi-p-phenylene)bismaleimidehaving the formula ##STR15##

The analytical data were as follows.

    ______________________________________                                        Infrared absorption spectrum:                                                 Group           Absorption Band                                               ______________________________________                                         ##STR16##      1700 cm.sup.-1                                                 ##STR17##      1762 cm.sup.-1                                                ______________________________________                                        N.M.R. spectrum:                                                              Group           δ Value                                                 ______________________________________                                        CH.sub.3        1.24                                                          CH.sub.2        2.86                                                          CH.sub.2        4.90, 5.22                                                     ##STR18##      7.07                                                           ##STR19##      7.12, 7.35                                                    ______________________________________                                        Chemical composition:                                                                        C           H      N                                           ______________________________________                                        Calculated Value (%)                                                                         73.24       5.20   6.57                                        Found Value (%)                                                                              73.19       5.21   6.54                                        ______________________________________                                    

EXAMPLE 3

Maleic anhydride (43 g) was dissolved in 250 ml of acetone. While thissolution was being kept at 18° C., 53 g of2,4-di(p-amino-phenyl)-4-methyl-2-pentene was slowly added thereto withstirring. The resulting reaction mixture was stirred at 18° C. for 21/2hours to formN,N'-(1-methyl-3,3-dimethyl-1-propenylenedi-p-phenylene)-bismaleamicacid having the formula ##STR20## At this time, the reaction mixture wasa yellow slurry. Then, 0.5 g of cobalt acetate tetrahydrate, 10 g oftriethylamine, and 50 g of acetic anhydride were added, with stirring,to the above slurry. After completion of the addition, the slurry washeated to 61° C. and stirred at that temperature for 8 hours, so that itbecame a clear brown solution. This solution was cooled to roomtemperature and, thereafter, worked up in the same manner as describedin Example 1. However, the amount of methyl alcohol added to thesolution was 80 ml and the amount of water into which the solution waspoured was 7,000 ml. As a result, there was obtained 80 g of productmelting at 99°-110° C. Its yield was 94% based on the amount of diamineused as the starting material. It was confirmed by infrared absorptionspectroscopy, nuclear magnetic resonance spectroscopy, and elementalanalysis that the product wasN,N'-(1-methyl-3,3-dimethyl-1-propenylenedi-p-phenylene)-bismaleimidehaving the formula ##STR21##

The analytical data were as follows.

    ______________________________________                                        Infrared absorption spectrum:                                                 Group           Absorption Band                                               ______________________________________                                         ##STR22##      1710 cm.sup.-1                                                 ##STR23##      1770 cm.sup.-1                                                ______________________________________                                        N.M.R. spectrum:                                                              Group           δ Value                                                 ______________________________________                                        CH.sub.3        1.53                                                          CH              6.21                                                           ##STR24##      7.11                                                           ##STR25##      7.25, 7.53                                                    ______________________________________                                        Chemical composition:                                                                        C           H      N                                           ______________________________________                                        Calculated Value (%)                                                                         73.24       5.20   6.57                                        Found Value (%)                                                                              73.20       5.18   6.60                                        ______________________________________                                    

EXAMPLE 4

Maleic anhydride (50 g) was dissolved in 120 ml of acetone. While thissolution was being kept at 15° C., 83 g of 2-chloro-4-isopropenylanilinewas added thereto. The resulting reaction mixture was stirred at 15° C.for 2 hours. Then, 0.9 g of cobalt acetate tetrahydrate, 16 g oftriethylamine, and 57 g of acetic anhydride were added, with stirring,to the above reaction mixture. Thereafter, the reaction mixture washeated to 60° C, stirred at that temperature for 21/2 hours, and thencooled to room temperature. After the addition of 50 ml of methylalcohol, the reaction mixture was slowly poured into 2,000 ml ofvigorously stirred water. The precipitate so formed was separated byfiltration and then washed with water, with an aqueous sodium carbonatesolution, and thoroughly with water. Finally, the precipitate was washedwith 150 ml of methyl alcohol and then dried at 50° C under reducedpressure to obtain 109 g of N-(2-chloro-4-isopropenylphenyl)maleimide ina 89% yield. The analytical data were as follows.

    ______________________________________                                                      C    H        N      Cl                                         ______________________________________                                        Calculated Value (%)                                                                          63.04  4.07     5.66 14.31                                    Found Value     62.95  4.09     5.61 14.28                                    ______________________________________                                    

EXAMPLE 5

The procedure of Example 4 was repeated except that the2-chloro-4-isopropenylaniline was replaced by 73.6 g of4-methyl-2,4-bis(3'-methyl-4'-aminophenyl)-1-pentene having the formula##STR26## As a result, there was obtained 103 g of product in a 91%yield. It was confirmed by infrared absorption spectroscopy, nuclearmagnetic resonance spectroscopy, and elemental analysis that the productwasN,N'-[1-methylene-3,3-dimethyltrimethylenebis(3'-methyl-1',4'-phenylene)]bismaleimidehaving the formula ##STR27## The analytical data were as follows:

    ______________________________________                                                     C         H      N                                               ______________________________________                                        Calculated Value (%)                                                                         73.99       5.77   6.16                                        Found Value (%)                                                                              73.87       5.72   6.14                                        ______________________________________                                    

EXAMPLE 6

The procedure of Example 4 was repeated except that the2-chloro-4-isopropenylaniline was replaced by 73.6 g of2-methyl-4-isopropenylaniline. As a result, there was obtained 101 g ofproduct in an 89% yield. It was confirmed by infrared absorptionspectroscopy, nuclear magnetic resonance spectroscopy, and elementalanalysis that the product wasN-(2-methyl-4-isopropenylphenyl)-maleimide. The analytical data were asfollows:

    ______________________________________                                                     C         H      N                                               ______________________________________                                        Calculated Value (%)                                                                         73.99       5.77   6.16                                        Found Value (%)                                                                              73.91       5.69   6.13                                        ______________________________________                                    

What is claimed is:
 1. Process for the preparation of analkenylphenylmaleimide having the formula: ##STR28## wherein R isalkenyl having 3 to 12 carbon atoms, R' is hydrogen, halogen or alkylhaving 1 to 4 carbon atoms, and n is a whole number of 1 to 4, or abismaleimide having the formula: ##STR29## wherein R' and R" can be thesame or different and are hydrogen, halogen or straight-chain orbranched alkyl having 1 to 4 carbon atoms, n and m are whole numbers of1 to 4, and D is an ethylenically unsaturated hydrocarbon group having 6to 24 carbon atoms, which comprises the step of effecting reaction of analkenylphenylmaleic acid derivative having the formula: ##STR30##wherein R, R' and n are as defined above for formula (I), or a lineardimer of like or different alkenylphenylmaleamic acid derivatives havingthe formula: ##STR31## wherein R', R", n, m and D are as defined abovefor formula (II), with at least one dehydrating agent which is acarboxylic acid anhydride in the presence of a tertiary amine, anorganic solvent and a catalyst, the catalyst being selected from thegroup consisting of: sodium sulfate, sodium carbonate, sodium phosphate,potassium sulfate, potassium carbonate, potassium phosphate, lithiumsulfate, lithium carbonate, lithium phosphate, iron sulfate, ironcarbonate, iron phosphate, nickel sulfate, nickel carbonate, nickelphosphate, cobalt sulfate, cobalt carbonate, cobalt phosphate, coppersulfate, copper carbonate, copper phosphate, manganese sulfate,manganese carbonate, manganese phosphate, sodium nitrate, sodiumacetate, sodium butyrate, potassium nitrate, potassium acetate,potassium butyrate, lithium nitrate, lithium acetate, lithium butyrate,iron nitrate, iron acetate, iron butyrate, nickel nitrate, nickelacetate, nickel butyrate, cobalt nitrate, cobalt acetate, cobaltbutyrate, manganese nitrate, manganese acetate, manganese butyrate,copper nitrate, copper acetate, copper butyrate, sodium pyrophosphate,nickel pyrophosphate, potassium pyrophosphate, lithium pyrophosphate,manganese pyrophosphate, iron pyrophosphate, copper pyrophosphate,acetylacetone complex of iron, acetylacetone complex of nickel,acetylacetone complex of cobalt, acetylacetone complex of copper andacetylacetone complex of manganese, to form the correspondingalkenylphenylmaleimide or bismaleimide.
 2. The process as claimed inclaim 1 the dehydrating agent is acetic anhydride.
 3. The process asclaimed in claim 1 wherein the catalyst is used in an amount of from0.001 to 1.2 moles per mole of the alkenylphenylmaleamic acid derivativeor the linear dimer thereof.
 4. The process as claimed in claim 1wherein the tertiary amine is selected from the group consisting of atrialkylamine having alkyls having 3 to 20 carbon atoms,N,N-diethylcyclohexylamine, N,N-dimethylbenzylamine, N-methylpiperidine,1,4-diazabicyclo[2.2.2]octane, 1,8-diazabicyclo[5.4.0]7-undecene andN-methylmorpholine.
 5. The process as claimed in claim 4 wherein thetertiary amine is triethylamine.
 6. The process as claimed in claim 1wherein the teritary amine is used in an amount of from 0.01 to 1.1moles per mole of the alkenylphenylmaleamic acid derivative or thelinear dimer thereof.
 7. The process as claimed in claim 1 wherein theorganic solvent is selected from the group consisting of chloroform,methylene chloride, carbon tetrachloride, acetone, methyl ethyl ketone,cyclohexanone, formic acid, acetic acid, butyric acid, methyl acetate,theyl acetate, butyl acetate, methanol, ethanol, propanol, ether,dioxane, tetrahydrofuran, 1-ethoxyethanol, 1-methoxyethanol,cyclohexane, benzene, toluene, xylene, mesitylene, chlorobenzene,cresol, dichlorobenzene, acetonitrile, pyridine, N,N-dimethyl acetamide,N,N-dimethylformamide, N-methyl-2-pyrolidone, N-methylcaprolacetam,dimethylsulfoxide and tetramethylene sulfone.
 8. The process as claimedin claim 7 wherein the organic solvent is acetone, methyl ethyl ketone,tetrahydrofuran or N,N-dimethylformamide.
 9. The process as claimed inclaim 1 wherein the reaction is carried out at a temperature of from 30°to 80° C.
 10. The process as claimed in claim 1 which further comprisesthe steps of, after completion of the reaction, adding an aliphaticalcohol to the reaction mixture and then separating the desired productwith the aid of a precipitant selected from the group consisting ofwater, methanol, ethanol, propanol, isopropanol, 1-butanol, 2-butanol,tert-butylalcohol, benzene, toluene, xylene, ethyl-isopropyl ether,ethyl isobutyl ether, chloroform and chlorobenzen.
 11. The process asclaimed in claim 10 wherein the alcohol is an aliphatic alcohol having 1to 4 carbon atoms.
 12. The process as claimed in claim 11 wherein thealcohol is methanol.
 13. The process as claimed in claim 10 wherein thealcohol is used in an amount of from 0.05 to 200 g per 100 g of thereaction mixture.
 14. The process as claimed in claim 10 wherein thealcohol is added to the reaction mixture having a temperature of from 5°to 40° C.
 15. The process as claimed in claim 10 wherein the precipitantis water.
 16. The process as claimed in claim 1 wherein thealkenylphenylmaleamic acid derivative is p-isopropenylphenylmaleamicacid.
 17. The process as claimed in claim 1 wherein the linear dimer oflike or different alkenylphenylmaleamic acid derivatives is a lineardimer of p-isopropenylphenylmaleamic acid.
 18. The process as claimed inclaim 1 wherein the linear dimer of like or differentalkenylphenylmaleamic acid derivatives areN,N'-(1-methylene-3,3-dimethyltrimethylenedi-p-phenylene)-bismaleamicacid or N,N'-(1-methyl-3,3-dimethyl-1-propenylenedi-p-phenylene)bismaleamic acid.
 19. The process as claimed in claim 1 wherein thecatalyst is a hydrated or unhydrated carboxylic acid salt of sodiumcobalt or nickel.
 20. The process as claimed in claim 1 wherein thecatalyst is a hydrated or unhydrated sodium acetate, cobalt (II) acetateor nickel acetate.